NASA earth scientist Compton Tucker has given new meaning to the old idiom, 'seeing the forest for the trees.'

At NASA's Goddard Space Flight Center in Maryland, Tucker has pioneered satellite monitoring of vegetation, using more than 30 years of data to track climate change, provide early warning of famine, chart deforestation and the spread of tropical disease.

"His work, in many respects, has been as influential as the image of the Earth seen from the moon. It allowed us to see, for the first time, how the Earth's vegetation reflects the seasonal pulse of the planet. Nobody else can claim these achievements," Darrel Williams, Tucker's supervisor and associate chief of Goddard, said.

Before Tucker's discovery, vegetation was simply classified and tracked according to the type of plant life found in a particular area. Tucker helped create the Normalized Difference Vegetation Index (NDVI), which uses a remote sensing system to monitor photosynthetic activity of plants and trees, to grasp the changing nature of ecosystems.

Satellite NDVI data is a key component of USAID's Famine Early Warning System, monitoring agricultural productivity as a means to prevent famine.

NDVI helped scientists predict a major Rift Valley fever outbreak in East Africa, for instance, enabling preventative measures to be taken four weeks before the disease appeared. The United Nations has used satellite data to predict insect infestations in Africa, Arabia and Southwest Asia, providing early warnings to avoid the destruction of crops.

Tucker's measurements also help scientists determine how much, carbon dioxide is consumed by plants.

"Understanding the consumption of carbon dioxide by plants has a global impact because it can provide data on the potential damage of global warming," Robert Dickinson, a professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, said.

Initially, Tucker said scientists didn't believe in the merits of his studies, but he did not let this sway his stamina. "I was interested in experimentation and was not nervous about changing techniques that didn't work," he said..

Earth scientists credit Tucker's NDVI work for establishing a worldwide standard to measure not just the number of plants and trees in a particular area, but how well they perform. "His genius is in his ability to take data that was qualitative and make it quantitative," Dickinson said.

"Dr. Tucker tirelessly maintained NDVI data for nearly 30 years. Every model of our ecosystem starts with Dr. Tucker's NDVI," Inez Fung, professor and co-director of the Berkeley Institute of the Environment at the University of California, said.

Tucker's 1985 breakthrough article in "Science" Magazine transformed the field of ecology by detailing how the NDVI could assess the vegetative state of a continent, such as Africa. A digitally- processed image showing the results made NDVI the cornerstone of global vegetation monitoring.

Tucker has penned more than 155 scientific papers that have been cited more than 12,000 times by other researchers. according to index measuring.

Tucker's admiration and respect extends beyond his scientific peers. In addition to his work at NASA, he lectures at universities, such as the University of Maryland, Baltimore. "He is known around campus for being very kind and modest, yet funny," said Fung. "Everyone loves him. He's got the twinkle in his eye."

This article was jointly prepared by the Partnership for Public Service, a group seeking to enhance the performance of the federal government, and washingtonpost.com. Visit www.ourpublicservice.org for more about the organization's work.